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Auger Electron Diffraction
The Auger effect (; ) or Meitner-Auger effect is a physical phenomenon in which atoms eject electrons. It occurs when an inner-shell vacancy in an atom is filled by an electron, releasing energy that causes the emission of another electron from a different shell of the same atom. When a core electron is removed, leaving a vacancy, an electron from a higher energy level may fall into the vacancy, resulting in a release of energy. For light atoms (Z<12), this energy is most often transferred to a valence electron which is subsequently ejected from the atom. This second ejected electron is called an Auger electron. For heavier atomic nuclei, the release of the energy in the form of an emitted becomes gradually more probable. Effect Upon ejection, the |
Auger Process
Auger may refer to: Engineering * Auger bit, a drill bit * Auger conveyor, a device for moving material by means of a rotating helical flighting * Auger (platform), the world's first tension leg oil rig; see ''Big, Bigger, Biggest'' * Earth auger, a drilling tool or machine used for making holes in the ground * Wood auger, a drill for making holes in wood (or in the ground) Science and technology * Auger effect, an electron effect in physics, named for the physicist Pierre Auger. Derived terms include: ** Auger electron spectroscopy, an analytical technique using the Auger effect ** Auger therapy, an experimental radiation therapy for the treatment of cancer * Auger shell or auger snail, a common name for shellfish of the family Terebridae * Auger shower, or air shower, an effect of cosmic rays hitting the atmosphere. Also named for Pierre Auger. Other uses * Auger (surname) * Auger Hill, a hill in Antarctica See also * Pierre Auger Observatory The Pierre Auger Observa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conduction Band
In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level, and thus determine the electrical conductivity of the solid. In nonmetals, the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature, while the conduction band is the lowest range of vacant electronic states. On a graph of the electronic band structure of a semiconducting material, the valence band is located below the Fermi level, while the conduction band is located above it. The distinction between the valence and conduction bands is meaningless in metals, because conduction occurs in one or more partially filled bands that take on the properties of both the valence and conduction bands. Band gap In semiconductors and insulators the two bands are separated by a band gap, while in conductors the bands overlap. A band gap is an energy range in a solid where no electron states can exist due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Physics
Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. Atomic physics typically refers to the study of atomic structure and the interaction between atoms. It is primarily concerned with the way in which electrons are arranged around the nucleus and the processes by which these arrangements change. This comprises ions, neutral atoms and, unless otherwise stated, it can be assumed that the term ''atom'' includes ions. The term ''atomic physics'' can be associated with nuclear power and nuclear weapons, due to the synonymous use of ''atomic'' and ''nuclear'' in standard English. Physicists distinguish between atomic physics—which deals with the atom as a system consisting of a nucleus and electrons—and nuclear physics, which studies nuclear reactions and special properties of atomic nuclei. As with many scientific fields, strict delineation can be highly contrived and atomic physics is often considered in the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiative Auger Effect
In optics and spectroscopy, the radiative Auger effect is a decay channel of an inner-shell atomic vacancy state, in which an X-ray photon is emitted accompanying simultaneous promotion of an electron into either a bound or a continuum state. Thus the transition energy is shared between the photon and the electron. The effect was first observed by Felix Bloch and Perley Ason Ross, with the initial theoretical explanation by Bloch. Later the effect has also been observed on defects in the solid-state, semiconductor quantum emitters, as well as two-dimensional electron gases. In the latter case, the effect is typically referred to as shake-up. See also *Auger effect The Auger effect (; ) or Meitner-Auger effect is a physical phenomenon in which atoms eject electrons. It occurs when an inner-shell vacancy in an atom is filled by an electron, releasing energy that causes the emission of another electron from a ... * Radiative transition References Atomic physics {{AMO-phys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Capture
Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. This process thereby changes a nuclear proton to a neutron and simultaneously causes the emission of an electron neutrino. : : or when written as a nuclear reaction equation, ^_e + ^_p -> ^_n + ^_ ν_e Since this single emitted neutrino carries the entire decay energy, it has this single characteristic energy. Similarly, the momentum of the neutrino emission causes the daughter atom to recoil with a single characteristic momentum. The resulting daughter nuclide, if it is in an excited state, then transitions to its ground state. Usually, a gamma ray is emitted during this transition, but nuclear de-excitation may also take place by internal conversion. Following capture of an inner electron from the atom, an outer elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coster–Kronig Transition
The Coster–Kronig transition is a special case of the Auger process in which the vacancy is filled by an electron from a higher subshell of the same shell. If, in addition, the electron emitted (the "Auger electron") also belongs to the same shell, one calls this a super Coster–Kronig transition. The Coster–Kronig process is named after the physicists Dirk Coster and Ralph Kronig. References * Atomic physics {{AMO-physics-stub ru:Переход Костера-Кронига ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auger Therapy
Auger therapy is a form of radiation therapy for the treatment of cancer which relies on low-energy electrons (emitted by the Auger effect) to damage cancer cells, rather than the high-energy radiation used in traditional radiation therapy. Similar to other forms of radiation therapy, Auger therapy relies on radiation-induced damage to cancer cells (particularly DNA damage) to arrest cell division, stop tumor growth and metastasis and kill cancerous cells. It differs from other types of radiation therapy in that electrons emitted via the Auger effect (Auger electrons) are released with low kinetic energy. In contrast to traditional α- and β-particle emitters, Auger electron emitters exhibit low cellular toxicity during transit in blood or bone marrow. Due to their low kinetic energy, emitted Auger electrons travel over a very short range: much less than the size of a single cell, on the order of less than a few-hundred nanometers. This very short-range delivery of energy permits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectric
The photoelectric effect is the emission of electrons from a material caused by electromagnetic radiation such as ultraviolet light. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, solid state, and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission. The experimental results disagree with classical electromagnetism, which predicts that continuous light waves transfer energy to electrons, which would then be emitted when they accumulate enough energy. An alteration in the intensity of light would theoretically change the kinetic energy of the emitted electrons, with sufficiently dim light resulting in a delayed emission. The experimental results instead show that electrons are dislodged only when the light exceeds a certain frequency—regardless of the light's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloud Chamber
A cloud chamber, also known as a Wilson chamber, is a particle detector used for visualizing the passage of ionizing radiation. A cloud chamber consists of a sealed environment containing a supersaturated vapor of water or alcohol. An energetic charged particle (for example, an alpha or beta particle) interacts with the gaseous mixture by knocking electrons off gas molecules via electrostatic forces during collisions, resulting in a trail of ionized gas particles. The resulting ions act as condensation centers around which a mist-like trail of small droplets form if the gas mixture is at the point of condensation. These droplets are visible as a "cloud" track that persists for several seconds while the droplets fall through the vapor. These tracks have characteristic shapes. For example, an alpha particle track is thick and straight, while a beta particle track is wispy and shows more evidence of deflections by collisions. Cloud chambers were invented in the early 1900s by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Victor Auger
Pierre Victor Auger (; 14 May 1899 – 24 December 1993) was a French physicist, born in Paris. He worked in the fields of atomic physics, nuclear physics, and cosmic ray physics. He is famous for being one of the discoverers of the Auger effect, named after him. Early life Pierre's father was chemistry professor Victor Auger. Pierre Auger was a student at the École normale supérieure in Paris from 1919 to 1922, the year when he passed the agrégation of physics. He then joined the physical chemistry laboratory of the faculté des sciences of the University of Paris under the direction of Jean Perrin to work there on the photoelectric effect. Career In 1926, he obtained his doctorate in physics from the University of Paris. In 1927, he was named assistant to the faculté des sciences of Paris and, at the same time, adjoint chief of service to l'Institut de biologie physico-chimique. Chief of work to faculty in 1934 and general secretary of the annual tables of the constants in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Drummond Ellis
Sir Charles Drummond Ellis (b. Hampstead, 11 August 1895; died Cookham 10 January 1980) was an English physicist and scientific administrator. His work on the magnetic spectrum of the beta-rays helped to develop a better understanding of nuclear structure. Education and internment Ellis was the son of Abraham Charles Ellis, a general manager of the Metropolitan Railway, and Isabelle Flockart Carswell. He won a scholarship to Harrow School where he excelled academically as well as at sport. In 1913, he became a cadet in the Royal Military Academy in preparation for a career in the Royal Engineers. He was holidaying in Germany the following summer when World War I broke out. All British nationals were rounded up and sent to the Ruhleben internment camp just outside Berlin. The camp had been a horse racecourse. During internment the detainees had a large degree of freedom. They had access to books, and Ellis made good use of his time to study. Another detainee in the camp was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
